In Sickness and In Health
by TheMadKatter13
Summary: SEQUEL TO 'THE APEX PREDATOR' A pregnant omega is a pleasant thing to have. A sick, pregnant omega is a worrisome thing to have. AU: alpha!KnightOfHell!Cas / omega!angel!Dean.


**In Sickness and In Health**

**by TheMadKatter13**

**SUMMARY~SEQUEL TO 'THE APEX PREDATOR' A pregnant omega is a pleasant thing to have. A sick, pregnant omega is a worrisome thing to have. AU: alpha!KnightOfHell!Cas / omega!angel!Dean.**

**DISCLAIMER~The rights to Supernatural reside with the WB and the CW and Eric Kripke (and probably a lot of other people that I'm too lazy to look up) and I receive no financial gain from the writing of this story.**

**AN~Writing demon!Cas who is still in-character is stupid-hard. ಠ_ಠ I did however watch the fourth gif in this gifset (TheMadKatter13 tumblr, tagged demon!Cas) the entire time because it helped keep me in line (also because holy shit demon!Cas is ridiculously hot in that gif. ಠ_ಠ )**

**In Sickness and In Health**

* * *

"I call on the angels Sam and Bobby for assistance." Castiel had chosen his location as carefully as he could, a wide open space in which he could fight if needed. For once in his life, he didn't want to fight an angel. He just wanted to get back to his. The flapping of wings that accompanied every angel's arrival sounded behind him and he turned to face whomever had arrived.

"Why should we not kill you where you stand?" The speaker wore a tall, muscular alpha meat suit with chin-length brown hair. At his side was a significantly older one, beta, mustached and bearded. From Dean's stories, he knew that Sam was alpha and Bobby a beta, and as long as those were actually the angels before him, then . Both were tensed for the offensive, their angel blades already in-hand. The demon was keeping calm and still, the best way to face off with these jumpy types. He never would have allowed himself to have been killed in the past, but now it was different. Now he had a mate at home with hatchlings in his belly. If he died, Dean died. If Dean died, their hatchlings died. Unacceptable.

"My mate's health is of great concern to me. I fear he is... not doing well." During Dean's heat, between bouts of need, the Knight had baited his new mate into conversation. When his angel had finally decided to speak to him for something other than begging for his power and his cock, the stories he'd told and the debates they'd had (his omega was delightfully fiery) only further enamoured him to his soldier angel. As time passed, it seemed that the attraction became mutual. Dean would begin to initiate not only conversation, but also affection, though the former was taunting and the latter was tentative. He hadn't even mounted his mate since his heat ended, not wanting to scare away his omega; he was a bit surprised the angel was still there with him as it was. When the Knight had to leave the rooms he claimed as his own, on his return, his angel's grace would reach out in shy tendrils, creeping along the edges of his power in hesitant welcome even if he refused to speak to or even look at the Knight. Castiel loved it.

As Dean's stomach had begun to swell with their offspring, the angel had begun to nest, demanding clothes and sheets, sporadically rejecting and accepting this fabric or that until the alpha realized that there was a pattern to the accepted offerings: they were all the ones imbued with his scent and his power. Piece by piece, these fabrics were gathered into the corner of Castiel's resting room and, when he began offering pillows as well, started to take the shape of a miniature cave, one which his mate seemed to spend more and more of his time inside, curling around his expanding stomach and folding his wings around his vessel. The Knight had left his angel to his instincts, quite aware that there was little chance he would be wanted in such an intimate a space. So he was quite surprised when a disguised offer was snapped out at him like a whip, muffled for its origins from deep within the nest, as he passed by one day, an open invitation to keep his omega company for the duration of his pregnancy ("Do you think I'm going to grow fat enough to fill up this space myself?"), the meaning behind the words belying the tone it was extended with. It wasn't the nesting that concerned him though; he already knew that his omega would be drawn to instinctively comply with such base instincts. Nor was the snappish manner in which he was treated by his mate, already used to the angel's rough demeanor and only finding it endearing.

He didn't expect Dean to want to leave his rooms and he had been right. The angel remained in his rooms, primarily the resting room. But mainly he spent his time in the nest he had created. When he did emerge from the miniature cavern of fabrics, the time he spent outside of it grew less and less the further along his pregnancy he got. _That_ was what had first ignited his concern. What _inflamed_ it was that when his omega did leave his nest, it became clear that he was growing weaker, unable to walk even around the edges of the resting room, slowly becoming unable to even stand up without assistance. Additionally, the longer his angel remained with him, the paler his vessel's skin became, even taking on what was likely a sickly pallor. The former actions he could attribute to omega nesting instinct, which he had no problem admitting that he knew absolutely nothing about, and the latter reaction he knew from experience of kidnapping and torturing humans that that was a normal human biological reaction to staying out of the sun. All of it he could explain away due to ignorance.

What he could not explain away or ignore was the way his angel's grace was slowly dimming. The glow had started out as bright as the sun above. Now it was no brighter than a torch. What he found even odder than that was that the more Dean grew to like him (evident in the increasing lack of gruffness in both voice and words), the faster his grace dimmed, but at the same time, remained completely and utterly pure, untainted, even the tendrils that extended to and entwined with the darkness that was his own power. Just as concerning was the state of the once-beautiful tawny feather's of his omega's wings. Every night, when he joined his mate in his nest, the angel's wings would flinch towards him in a strange aborted motion that Castiel finally realized was his mate wanting to be preened but either afraid to ask for affection from a demon or unsure how to ask his new mate. Without a word, he would indulge, smiling at his brave soldier's shyness as he immersed his fingers in thick feathers, sorting and soothing. He kept his stroking both firm and gentle, comforting, not unlike that first time, only without the mating oils slicking his way that would only appear during his omega's heats. But his feathers... as Dean's grace grew dimmer, the feathers on his wings started to wilt like plants in winter's chill. It concerned him so to see those feathers in such poor condition but it seemed that no manner of affection he could bestow on his mate, no manner of kindness, could or would improve his condition.

The Knight began spending so much time in his rooms with his mate trying to fix him that demons weaker than him, direct subordinates or otherwise, began to challenge his Knighthood when he did venture to other parts of Hell. They thought that, because he had taken a mate, particularly an angel-mate, that he had grown weak, sentimental. It was true that he had grown sentimental, he cared more for his omega than he had cared for anything in his life as a human or as a demon, but that only made him stronger. Challenges to him or his mating-claim were met with swift deaths or torture, depending on the nature of the threat: death for those that challenged him directly, torture for those that challenged his mating-claim, slow and painful torture for those that threatened his mate. When he was done, their meat suits, or what was left of them, were strung up in common areas as a reminder that he was still a Knight and taking a mate, no matter their race, did not diminish his power, did not make him any less dangerous. In fact, he liked to think it made him even more dangerous, his drive to protect his mate even stronger than his will to live or his urge to dominate. He had never told Dean about any of the challenges or threats, and there had been plenty of both. Castiel was determined his mate never know.

Castiel had debated long and hard about what he could possibly do to help his angel. He had consulted with those he could possibly trust on the matter (the number of which were few and far between but which spanned numerous species). Finally, when nothing worked, not mating, not scenting, not preening, no potion or spell, he was forced to come to terms with the fact that angels were likely the only thing left that could save his mate. So here he was, conversing with the two angels his mate spoke most of.

"As fascinating as it is to hear a demon claiming to care about another, why would we care about some demon whore?" Bobby, tone condescending. The Knight snarled.

"My mate is neither demon nor whore," he snapped back, angry at the insult. Yes, it would be incredibly interesting to see his mate as a fallen, but would he be the same? Perhaps, perhaps not. For now, it was not worth it to try. He looked away for a moment, bringing his composure back under wraps. Now was by far the worst time to say the wrong thing with the life of his omega and his hatchlings on the line.

"Fine, human, whatever," Sam replied just as easily.

"Neither is he human," Castiel said, voice calm once more. Finally, he seemed to have said something that caught their attention.

"Then what is he?" the tall angel inquired, eyes narrowed suspiciously.

"Two months ago, your garrison waged a battle in Hell. Every angel but one returned, yes?" Both angels, having relaxed slightly from the lack of threatening on his part, tensed immediately, angel blades raising in preparation of attack.

"What do you know of him?" The possessiveness in the other alpha's question set his nerves on edge. He tried to remind himself that the alpha called Sam was a hatch-mate of Dean's, had never fucked him, was simply worried about him in the same way Castiel now was, but still... the omega angel was his and he wouldn't give him up for anything or anyone.

"My mate is very weak," he said by way of an answer. "He is unable to travel by his own means and I do not trust my own to get him to our destination safely. it would be best if you were to go to him."

"As far as traps go, that's not a very good one." They were both looking sceptical now. He didn't answer them. At least, not with words. He could say all manner of pretty things. He could show them his angel's blade or the clothes he'd been wearing when he'd first arrived (he was clad only in Castiel's things now, if anything at all). But his words couldn't be trusted and any demon could have killed the omega and taken weapon and clothes. Slowly, he let his power flow outwards, concentrating on showcasing the tendrils of grace threaded through his darkness, proof of their bond. Both angels's eyes went wide.

"As I said, my mate is very weak and I am concerned about his wellbeing," he murmured into the quiet clearing. "I don't know how to fix him and I need answers now, not later. If you feel uncomfortable coming alone, have the rest of your garrison accompany us. I don't care." The two angels traded looks and then they nodded at each other, almost in sync. "Will you require accompaniment or can we get moving?" He didn't bother hiding the impatience in his voice, now that he'd convinced them. They both glared at him but the bearded one waved 'Go on' and he nodded once before using his own powers to return to Hell, the same cavernous area in which the initial assault had started two months ago. The angels Sam and Bobby appeared shortly after, alone, angel blades tight in their hands, obviously on edge and looking about warily as they followed him to his rooms.

Their postures and reactions reminded him of when he'd first come across his mate, following the calls of demons trailing an angel separated from its garrison. He hadn't expected to find an _omega_ angel, aggressively occupying and protecting the corner of a room empty save for the corpses of those he had already killed. The grace he had exuded had attracted Castiel immediately, and then when the Knight had flashed his own power, the silly thing had rebelled instead of submitting, fighting the instincts brought about by the heat tickling the alpha's nose. Then the angel had further surprised him by shooting forward, barrelling into him and knocking him into the surrounding wall before disappearing down the hall. He had been intrigued before, but in that moment, he had become both intrigued and aroused. He'd fought angels before, but none had ever been so deliciously... _defiant_. Even demons tended to cater to his whim without much fuss. Of course he gave chase.

As he had followed the scent of angel and of omega, both scents so incredibly _tantalizing_, the scent of heat had increased along the way, detailing exactly how far along the omega was. When he was close enough, the angel having just come into his sight, he had sent out a blast of solid power. The angel's wings had stuttered, interrupting his flight and sending him careening into his own section of wall. A moment later, when he'd crawled out, the Knight had hit him again, driving the pretty thing to all fours (and oh did he look pretty like that). Each insult the angel had spat out only made the demon want him more, each act of resistance, like trying to threaten him with his wings, only serving to arouse him further.

When he picked up the unnamed angel and it passed out in his arms, he carried it to his rooms. As he walked, and as he laid the omega on his bed and undressed him, he spent the time loosing little bits of his power, small piece by small piece, letting what was about to be his new mate adjust to him subconsciously. Finally, when all of his power was free and surrounding his angel, the omega had woken up in full throes of heat and he obliged ever so graciously in what his new mate begged of him. He couldn't have been more pleased then that he had been the one to come across the angel and the same was not only true still, but was even stronger than when it had first appeared. Even now, as he approached his resting room, the (worryingly diminished) tendrils of Dean's grace reached out to greet him, tickling at the edges of his power like the cautious way his mate's fingers tended to brush his clothes when he wanted affection but didn't seem to know how to ask for it.

"Cas, you shithead, you said you'd be here when I woke up. Now hurry up and get in here and hand me something I can throw at you for being a liar." His mate's voice echoed down the hallway to greet him and he smiled at the demand, a true smile. Dean was the only soul for which he really would truly smile, rather than the more sarcastic smirk or sneer he would use to put opponents and prey at unease. He couldn't quite help it. That his mate was calling out to him, greeting him, desiring his presence during such a vulnerable time as slumber, wanting him to be there, giving him a nickname (rude or otherwise)..._threatening_ him (_him!_, a Knight of Hell!), pleased him. _Immensely._

"Apologies, beautiful," he called back as he entered the room. His mate was sitting up in his nest, vessel naked, gaunt face pinched with annoyance and enough caution to justify the angel blade raised and poised for defense. "Will you finally be using that on me?" the Knight asked, gesturing at the weapon as he approached. Dean's annoyance visibly increased, the evidence apparent in the deepened frown even as his cheeks flushed lightly while he lowered the weapon.

"No, of course not, you idiot," he snapped as Castiel bent at to the waist to press a kiss to his temple. The demon delighted in the way his angel's grace pulsed whenever he did that, as if he was blushing all the way down to his soul, and indeed the flush on his face darkened simultaneously. Despite the omega's harsh tone, when the Knight moved to draw back, a hand curled around the back of his neck, pulling him back down and a nose trailed slowly along his neck, small _whuff_s of air indicating his omega was scenting him in a returned greeting. The hand stayed firm around the back of his neck when the nose left his scent gland and lips tickled at his ear. "But just because I won't use this on you," the angel whispered, "doesn't mean I won't use this on your friends."

The hand on his neck loosened but Castiel only leaned back far enough to stare down into bright green eyes. The angel's chin was lifted defiantly even though doing so exposed the full length of his tanned neck. Normally an omega exposing their neck like that meant submission, but when Dean did it, it was meant as a challenge and it came off as one: 'come and get it; if you think you can'. The dare, regardless if it was accidental or intentional, never failed to arouse the alpha, and when his omega's nostrils flared and those pretty eyes (tense, concerned, _trusting_) widened and turned interested, he knew his mate had caught the faint scent of his arousal. For another moment, he marveled at how they'd gotten to this point, the point where his angel _was_ finally beginning to trust him, was becoming worried about him for when he left the nest for _him_ rather than just the continuance of their bond and his own life. He could only hope it was legitimate feeling and not merely caused by nesting instincts that would disappear when their fledglings hatched. After all, matings only went skin deep. The Knight smiled then, pushing his concerns to the back of his mind for the moment and delighting in being able to watch his mate relaxing beneath him as he leaned down to palm the swollen stomach and to press a kiss against his omega's neck before moving his lips to his mate's ear in turn.

"If anyone comes into this room without me, I would encourage you to dispatch them in whatever manner you desire," he whispered. Dean met his eyes again, and then nodded, expression gone somber. He smiled again in assurance. "Now, I _did_ bring company but they're not _my_friends." Dean tensed at his words, eyes darting to behind him when he stepped aside to draw attention to the two angels still lingering in the doorway.

"Sam?! Bobby?!" Dean cried, his tone as shocked and disbelieving as the look on the faces of both newcomers. Then his face broke into a wide smile, wider than any Castiel had yet seen on his mate and he felt a flood of anger that his angel would smile like that for someone else but not him. "Sam! Bobby! Shit it's good to see you!" A second later, the angel was struggling to get up and both of the other angels started forward only to halt when Castiel growled and sent out a blast of power in warning. Dean glared at him. "Cas! Calm down. Fuck. If you're going to throw a fit about them helping me up, then you better get your ass over here and do it yourself."

Castiel ignored the surprised look on the faces of the visitors (further surprise that a demon would help anyone) and moved from Dean's side to his back, wrapping his arms carefully under his mate's to hoist him to his feet, always remaining _excruciatingly_ aware of the pregnancy just below his arms. His angel's vessel was unclothed, as it had been the last few weeks, and while angels and demons didn't care about clothing their vessels for any other reason to blend in, the Knight couldn't stand having his mate so exposed so he pulled off the tan cloak his meat suit had come with and wrapped his omega in the fabric, closing him away from the eyes of the others. Dean rolled his eyes but wisely said nothing. Once he was fully covered, the Knight pulled the angel blade from his mate's loose grasp, standing guard at his back. If they attacked, he may have to defend from over his omega's shoulder or simply get his angel out of the way. His power was pulsing just under the surface, barely leashed, prepared to lash out in either a second warning or in attack. They may have been his mate's brothers, but a mated alpha could only stand another standing so close to their omega, especially another alpha.

"We're so happy you're alive, Dean," Sam said, tone and expression one of deep concern and wariness. "We looked for you after the battle but none of us could find any trace of you. We were all worried. We feared the worst." Dean laughed and looked down as his hand raised to rub at his pronounced belly. Castiel couldn't see his face but his grace was calm, not roiling or lashing about, and his tone was gentle, tenseless.

"No, definitely not the worst." The omega stayed that way for a minute before his head snapped back up and the alpha could see that same flush as always crawling backwards from the front of his neck and up his ears as his hand fell back to his side. "Uh, anyway, this is my alpha, Cas. Er, Castiel, technically." The only one who ever called him anything other than 'Castiel' was his mate; no one else would ever dare to do such a thing. He had killed for less, not that Dean knew. He doubted the angel would care if he did, might even increase the name calling, just because he could.

"Wait," Sam said, eyes frowning and grip on his weapon tightening. Castiel tensed, his shoulders drawing back as he placed his unoccupied hand on his mate's waist. "Castiel. As in the Knight of Hell, Castiel? That's your mate?" Would they kill their brother to get rid of him? He had quite the reputation, and for good reason, and he had no doubts that he was wanted dead as much as the others of his order, perhaps more, considering this current situation.

"Yeah, who would've thought? Me, mated?" Dean laughed. Both angels gave him an incredulous look.

"Dean, I'm more concerned that you're mated to a Knight than I am about you being mated in general," Bobby finally spoke up, eyeing the demon standing guard over the omega's shoulder, gaze flicking down to the angel blade dangling blatantly from his grasp next to his omega's thigh.

"Yeah well," the omega shrugged. "That's what I get for going to battle right before a heat." He let out a chuckle that sounded forced. Something in the demon's centre felt odd at the thought that his mate resented their bond. "Anyway," he cleared his throat, "what are you guys even doing here?" The two visitors looked at one another and then back at Dean.

"The demon said that you weren't doing well. And it's right. You look terrible." His omega's chin dropped, his head moving slightly from side to side, as if taking in the way he looked.

"Cas?" Dean turned his head to look at him from over his shoulder, expression troubled. "How did you even know?" The Knight pulled his free hand from the hip it had been resting on and rose it to stroke lightly along the top of a wing. He couldn't see his mate's expression but as the faint scent of arousal tickled his nose, making one corner of his lip twitch, he could imagine eyelids fluttering over those pretty greens.

"I'm your mate, Dean. I will always know when you are unwell." This time his angel twisted at the waist to look at him and the smile he received at those words was tremulous and shy but appreciated none-the-less. "You grow dimmer every day. Why did you not say anything?"

"I didn't want to...worry you." Despite his words, the way his angel didn't meet his eyes told him that despite the tentative trust built up between them, it wasn't his _concern_ Dean was worried about, but rather whether or not he would even _care_. No matter. He would have plenty of time to prove his devotion later.

"You are my treasured mate. Your health will always worry me." There was that pulsing in his grace again, the soul-deep blush to accompany the Hellfire-bright flush on his vessel's face.

"That's ah... that's... thank you." He smiled and pressed a kiss to a warm cheek, though the second his lips let off skin, all emotion cleared immediately from his face as he turned his attention back to the other two.

"Now that you have seen him, what must be done?"

"This is...unprecedented, as far as matings go," the beta said, scratching at the beard on his chin absently. "But in the past, pregnant angels who spent time outside of Heaven have been known to grow sick the longer they remain away. Surrounded by so much darkness cannot be good for Dean. The hatchlings... being half-breed, they are made of as much light as they are dark. Location will not matter to them. But Dean must return with to Heaven if he is to survive the birthing."

Castiel wanted to snarl-torture-_kill_ the one suggesting he be separated from his mate for any length of time during his angel's pregnancy, but he restrained himself to just wrapping an arm around Dean, palming his stomach. His omega would never be so vulnerable in his life as he would be when pregnant or birthing. But it was their best chance to improve his mate's health, to get him well enough to last through his pregnancy and the birthing.

"How long must he remain there before he is at full health again?" The beta shrugged.

"Like I said, this is unprecedented. On many levels. There is no telling. He may have to stay there through the birthing and all the way to the end of nesting." Now Castiel did frown, his attitude darkening.

"And the survival rate for omegas who go through pregnancy without their alphas?" Dean tensed at his words, as if he hadn't realized that the Knight couldn't go with him.

"Wait, Cas-"

"Not the best but... better if family nests with him before, during, and after," the beta cut in.

"No, Bobby-" So the beta was 'Bobby'.

"We'll keep you safe," Sam interrupted this time. The darkness in Castiel throbbed angrily at the thought of some other alpha wrapped around his mate.

"Sam!"

"Dean." His angel turned in his arms and he was both satisfied and placated to see a stricken look on his mate's face.

"Why can't you come with me?!" Dean's voice was angry, so very angry. He tried to not let it arouse him, now wasn't the time, but the dilation of his omega's eyes and the minor flaring of his nostrils told him that his mate caught the traces anyway.

"Because it's Heaven, angel," he murmured, reaching up to cup his face. His thumb stroked lightly along the stubble growing on the jaw of his angel's vessel. Dean's eyes fluttered and then closed as he tilted his head to press his cheek into the curve of the Knight's palm. "You know as well as I do that I can't go there." His mate huffed, a large, annoyed exhalation.

"Yeah, I know. I know. I just..." His mate trailed off and sighed again. "...wish you could," he finished in a murmur, eyes staying close and cheek resting in his alpha's palm. The Knight's lips twitched as he pressed them against his omega's forehead.

"I know." He stayed there for a minute before standing back, green eyes blinking open to watch him raise the angel blade. The other two angels started forward but Dean held up both arms, stalling them as he waiting patiently for whatever his demon was about to do. And _there_was the trust. Shame it was finally coming just as they were to be separated. He rolled up his sleeve and drew the silver tip along the length of his forearm. The blood welled up immediately as he opened the tan cloak covering his omega. Swiping his fingers through the blood, he began to draw right on the bulbous girth containing their eggs. His mate watched curiously.

"I haven't seen this symbol before," the angel said, reaching down to poke at the one he meant. Without looking away from his work, Castiel smacked away the offending finger before it could mess up his work. There was an annoyed sound from his mate as a hand _whapped_ him in the side of his head but, used to his mate's somewhat violent tendencies, he ignored it.

"That's because," he said slowly, finishing the last symbol, "it is mine." He closed up his sleeve as he eyed what he'd done, making sure there were no mistakes; an unquenchable anxiety drove him to perfection. "Unlike others of my order, I am more private. I do not appreciate being called from my work and so I do not like my symbol being common knowledge. Now, hold this." He handed his angel back his weapon before sinking to his knees, sliding both of his hands onto Dean's stomach, making sure not to disrupt his work.

Slowly, he blew hot breath along each curve and swipe of blood, drying it where it lay. It only really needed to stay in place until his omega could get to heaven and write it down on something more lasting. With each puff of air he let out, he let his fingers stroke along the edges, memorizing the way his omega felt in his hands. He had done the same thing each time they had lain in their nest, running his hands along wings and arms and legs and chest and stomach, trying to acclimate his omega to his touch outside of a heat. He hadn't been able to get far, hadn't thought he would have a time limit on such things. The light around him dimmed and he looked up to find his mate's wings wrapped around him as a hand slid down his face to cup his cheek this time.

"Get up here, you idiot," Dean snapped at him, voice low and cheeks flushed. Grinning, he went to his feet again, the wings around him constricting to keep him close. The grace along his power was thick now, thicker than it had ever been as it covered the edges of his darkness, almost dancing with it. Just like his affection-shy mate to try saying goodbye without even touching him or saying anything. He snorted.

"Now who's the idiot," he replied. "Did you really think your alpha would let you leave with just that?" A look of confusion came over his angel's face and he smirked before diving in, devouring his omega's mouth with his at the same time his power swelled and consumed his angel's grace. Dean went limp in his arms, fingers clutching at the fabric over his ribs. The wings around him disappeared, and he could almost see the way they would drape to the floor, beautifully submissive in the way his omega only became when overwhelmed with Castiel's more amorous advances.

He kissed his mate with all the pent-up hunger he'd been holding inside since his mate's heat ended, since he'd last mounted his angel. All the sexual frustration he'd hid to keep Dean comfortable in his presence was unleashed all at once, not knowing when he would even get to see his mate again, let alone his hatchlings. Underneath him, his angel remained pliant to his needs, the grace surrounded by his power calm in contrast to the roiling, angry darkness. As his hunger cooled, he began to soften his kisses in preparation to pull away when suddenly Dean's arms were around his neck and he was wrapped in soft wings once more and his kisses were returned with a vigour that confirmed that the arousal he had smelled from time to time went deeper than instinctual urges.

The last time his mate had been this responsive had been during his heat, and within seconds, Castiel's instincts were riled to rut-level. His hands reached down to hook around Dean's thighs, hoisting him up and around his waist as he turned around, slamming his omega's back into the wall. His mate was bucking beneath him and crying out as he began mouthing at his neck. Mating marks could only be renewed during mating, and since he hadn't been able mate his mate since the omega's heat, he hadn't been able to renew the mark either, and he was quickly growing annoyed by the angle failing to give him access. Legs wrapped tight around his waist, fluctuating rhythmically as his omega thrust his own erection into his with what little leverage he had.

"Cas. Oh, _Cas_," Dean whispered against his neck, voice sounding beyond wrecked. He growled lowly, nipping at the skin below his teeth as he continued to thrust. He need to be inside his angel and he needed to be inside him now. He used his hips to hold his omega in place, careful to not put too much pressure against their eggs, trying to reach between them to free his aching erection. Suddenly there was a swelling of grace around him, grace that was not his mate's and he broke away from his omega's neck with a snarl, hand already relieving his angel of his blade and raising it in defense of his mate and hatchlings.

There were two angels behind him. Two familiar angels. He blinked. And then he blinked again. The Knight took in the way the other two angels were staring at him, the way their graces and their blades were poised to strike at him for taking too much of a liberty of their brother.

"Cas?" Dean panted out, voice plaintive. Slowly, logic returned to him and he gently set his omega back on his feet. When he moved to take a step away, he found fingers wrapped in his shirt, keeping him close.

"Sorry, beautiful," he murmured as he fixed the cloak back over his mate's form. "I'll get dangerous if I keep going with company around. Maybe even to you."

"No, you'd never hurt us like that," he was told with unwavering conviction. _Us_, Dean had said. Castiel smiled as he raised his hand to clamp around the back of his omega's neck, the strength in his fingers a poor substitute for his teeth but a substitute nonetheless and his angel collapsed against him. For the last time, the Knight scented his mate as he slowly turned them around. The other two angels had relaxed just enough now and were now waiting to take their brother away, still posed to collect.

"No. No I wouldn't." Suddenly, Dean turned away from him and he blinked in surprise at this sudden departure only for tawny wings to flinch towards him in a familiar aborted move. He smirked and began to groom, faster than he ever had but no less gentle, no less firm, no less thorough. His angel was becoming relaxed again under his ministrations though the other two angels were getting less so the longer they remained in Hell. By the time he'd reached the final feathers, his mate was as relaxed as the other two were tense and leaning back against him. Castiel nuzzled his temple before whispering in his ear, "Time for you to fly back to the nest, angel."

The other two started forward, hands extended as Dean turned around to face him-

"Fuck no. Cas, just wait-" and then their hands landed on his shoulders and in a blink, all three angels were gone.

**.oOo.**

Time after his mate's return to his own home passed in much the same way as it had before he'd even had a mate: he killed and captured and tortured and maimed. But now he did it without stop, not sparing a moment to do anything other than his duties. He delivered orders and ignored the ones he'd received that he didn't like, same as always. Any thing to ignore the hole in his room where his angel had lived.

He hadn't expected to feel his omega's absence so strongly. Even stranger, it wasn't his instincts as a mated alpha that were yearning for him, but the hollowness in his chest. The same hollowness that had appeared when he'd first became a demon but had gotten used to as the centuries (millennia?) passed was as prevalent now as it has been in the beginning. Nor had he expected to feel the passage of time as a human did but there was no doubt that he was. He was torturously aware of days and nights, each one dragging itself out to emphasize his missing omega. So very torturously aware.

When exhaustion pulled at him, it was soul deep, but he couldn't rest. At least, not in his rooms. Each time he tried to return to them, memories did as well, and he could only sit in the remainder of Dean's nest remembering how his mate had felt in his arms. So when it got to the point that he did need rest, he would return to Earth, find a somewhere secluded with no trace of angel or demon or human or anything else, and there he would remain until enough physical strength returned that he could return to his duties with.

It was a strange thing to feel sentiment again. Unexpected. He couldn't even remember what it felt like when he'd been human. But Dean, of course he had to be special. Being an angel wasn't enough. Being an omega wasn't enough. He had to develop an attachment. Hardly his angel's fault though. He had tried to escape in the very beginning, before Castiel had marked him. But he hadn't tried to leave after that. The Knight could only guess why.

As time went on without a summons, doubt began to wear at him. Why had Dean stayed? Now that he was back home, would he even want to come back to his demon mate? The two angels that had come for him had said his omega and their hatchlings may survive the birthing if family nested with the angel during the pregnancy. Who would be nesting with him? Other omegas? Betas? Alphas? What reason could he have to even keep their half-breed fledglings or their bond when he had an alpha of his own race that he might actually want? If Dean went into heat after their eggs were delivered, would he allow another angel to mount him like he had in the past? Would he allow that alpha to bite over his Knight's mark? Endless 'what if's ate at his mind as days and nights went by with no sign of his mate.

Dean had been two months pregnant when he went home. How long were angel pregnancies? How long until his mate gave birth? He had no reference to go off of. Both human and demon omegas were live births and mating habits of birds were of absolutely no assistance. Was being in heaven healing him at all? The grace veined through his power was forever still and quiet, bright against the darkness in such a way that he couldn't determine if it was growing weaker or getting stronger. The presence of the bond in his chest was the only proof that that his mate was still alive; and for now, still his.

**.oOo.**

The tug on his center woke him from one of his rare bouts of rest and, judging by how poorly he still felt, he hadn't been at rest for long. But his anger at being awoken evaporated the second he realized how it was that he had been woken.

He was being summoned.

Without another though, he allowed the summons to call his form to its source. Where he arrived, it was to a place full of light so bright that he had to close his eyes. It was brighter than the sun, like how Dean's grace had been when the Knight had first captured him. And almost immediately, when grace upon endless grace piled on top of him, surrounded him, restricting every part of him, he knew why it was so bright. Had he been at full health, he may have been able to fight it off, or at least remained on his feet instead of collapsing to all fours under the weight of it all. But weak as he was now, weak as he'd been since his mate had gone, he didn't stand a chance.

"Dean?" he rasped out, his meat suit's voice not having been used since he'd last spoken to his angel. None of the graces jailing him, and there seemed like more than he could count, were his mate's but that did not mean his mate was not there, waiting somewhere in the outskirts.

"Cas!" Dean. He was there after all. He started crawling towards his angel's voice before his sight had cleared, seeing only white even from behind his eyelids, only to run in to the kind of barrier that told him he was in a Devil's Trap.

"Dean!" At finding himself trapped with his mate so close and calling out for him, the alpha in him, sleeping these last two months, reared its ugly head. His power responded in kind, swelling against his confinement. "Dean!"

"Cas!" His mate's voice was so close, his grace and his scent kept from the demon, but he knew it was there. So did The Alpha.

"DEAN!" he roared, power exploding in the spell-jail, the floor below him cracking until the trap broke and he could smell his mate. His eyes snapped open and still he could only see white but his nose and his ears were enough. He dove towards his angel, feeling familiar grace rising to greet him, his power swelling in return, enveloping his angel's brightness, engulfing it entirely, as his omega's scent thickened in his nose. Several stinging points of pain lit up across his body and he snarled at whatever the cause was but did not change course.

Bare, warm skin met his questing fingers and he wasted no time in turning his omega around and forcing him to the ground, following close behind, ignoring the continuing spots of pain. The alpha likely ripped the fabric covering his erection in his haste but he couldn't spare a thought to care. In seconds, the Knight was pressing inside a slick heat he hadn't felt for eight agonizing weeks. There was a cry of pleasure from his mate and the grace cocooned in his power throbbed as he began to thrust.

There was no ceasing of his hips even as he draped himself along his angel's back, careful of the tawny wings pressed between them even in this state. Sounds of enjoyment continued to echo in his ears as his cock pummeled his omega's sopping hole. His knot was expanding and started to catch on his mate's rim with every thrust and the cries from below him were losing consistency. Pain lit up across the entirety of his back all at once and he roared his anger at someone trying to pull him from his long-absent mate. He was too close.

The demon dug his fingers deeper into his angel's hips, refusing to let go and refusing to be made to let go. His knot was too big to slip in and out now but orgasm was coiled and ready for release and so, with a snarl, he sunk his teeth into his fading mating mark, shoving his knot in right before it expanded with his orgasm. His angel was trembling below him with his own orgasm evident in the way his passage was clamping down on his mate's knot almost painfully-hard.

The attacks on his back ceased abruptly as the alpha's cock continued to deliver semen into his pliant omega, refusing to release his mate's neck from his jaw until his knot deflated. The angel below him was writhing in pleasure and crying out, sobbing, his grace brightening and brightening until the Knight, coming back to himself, thought it might've been more bright than when his angel had first become his. Slowly, carefully, he pulled his teeth free from the ripped flesh and gently licked away the blood, his alpha saliva healing the omega skin as he eased his grip on his angel's hips, sliding his hands around and across the pregnant belly between them and the floor.

"_Cas_," Dean moaned as the alpha's knot deflated and his cock slipped free.

"Dean," Castiel whispered back, nuzzling the mating mark and rubbing his palms against the distended skin in the way he remembered his mate liking, hoping it hadn't changed. "I missed you, angel," he confided, just as quietly, nose pressed to a sweat-damp neck as he inhaled the long-missed scent of his omega.

"Fuck, I missed you too, Cas." His eyesight was coming back slowly, the white fading bit by bit. He expected the skin in front of him to look as healthy as when his angel had first become his but instead, it looked worse than when he'd left. He frowned heavily, leaning back until he could sit and cross his legs, carefully pulling Dean into his lap and turning them eye to eye. The angel's face was a sorely missed sight, but it was gaunt, pale, dark bags under dull green eyes. Anger and despair twisted his insides into a knot.

"I let you leave my side so you could get better, beautiful," he growled, pressing a palm to his mate's cheek, grasp firm. "Not so you could get worse." Dean shifted around him, straddling his thighs and bracing his hips with bony knees while he wrapped arms just as bony around his neck. Slowly, tawny wings curled around him as a nose pressed against the scent gland on his meat suit.

"Didn't do it on purpose, asshole," was muttered against his neck. He smiled as he moved to mirror his omega, wrapping his own arms around a waist only as thick as it was because of the pregnancy pressing against his own stomach. He closed his eyes, just breathing in the scent of his mate.

"That is why we called you here," a new voice spoke up, one that he recognized from when Dean was taken from him. For a minute, he ignored it, wanting nothing more than to soak up the affection he hadn't quite realized he was starved for. "Do not ignore me, demon."

"My mate takes precedence over any of your concerns," he snapped, tightening his arms.

"And if your mate _is_ our concern?" the same voice, Sam?, snapped back. Finally, he opened his eyes again and raised his head, finding his eyesight had returned. The alpha and beta angels that had taken his angel back to heaven were standing a respectable distance behind Dean, watching them. He tightened his arms, feeling suddenly and incredibly vulnerable sitting on the floor with his omega in his lap. There was no question that he was in heaven, being surrounded by as much grace as he was and the whiteness that had obliterated his vision since arriving. What was questionable was how they managed to get him here in the first place. And how they had failed to fix his mate.

"Then by all means, elaborate." Dean's wings and arms tightened around him at his tone, a soft tongue lapping along his neck in an attempt to comfort him, relax him.

"It seems that, even being back in heaven, the lack a present mate has worsened Dean's condition, instead of improving it." The beta, Bobby?, spoke this time, face pinched with concern. Castiel shifted his arms down, hands bracing under his mate's rear and holding him there as he stood, Dean's legs, arms, and wings tightening about him as a strange squawk of surprise was let loose against his neck.

"Cas, you shithead! Warn me before you do that!" His lip twitched but he stayed silent and for the most part, ignored his mate's rebuke as he gently set him back on his feet. His omega was still wearing his cloak and there had been a familiar shape along his mate's chest that he'd recognized when they'd been pressed together. The angel blade was in his hands and poised for attack within seconds.

"Is there a reason I shouldn't kill you for bringing further harm to my mate and endangering the lives of our young?" The air around them was quiet but Dean was tense, now, at his side, fingers fluctuating in his top as if he wanted to stop his alpha but didn't dare get between this fight, not with his condition. Bobby tilted his head and smirked.

"You attack us, we defend. We defend, you die. You die, your mate dies. Your mate dies, your young dies. Simple as that." The Knight stayed motionless for a long moment before he twirled the blade, pressing it harmlessly along his forearm. Dean relaxed against him. "Now, if you're quite done, we have taken a great deal more time on you than we have on any demon, getting you up here so that you could assist in the healing of our brother. You have been here for a short time yet your mating has already managed to improve Dean's grace beyond what it has been. Continue to improve him, do not cause problem, and you may continue to stay." With that, the beta nodded at Dean and Dean nodded back before tugging at his sleeve.

"Come on, you idiot. I had to build another nest." The room around them was small with one door that led to a tight hallway. A strategic summoning location, should he have attempted to attack at any point after his arrival. Once again though, he was surrounded by angels but his mate was his priority. Once they passed through the narrow hallway, it led to a much longer one with door after door lining its sides. As they walked along, one arm around his mate's shoulders, he could smell Dean's scent getting stronger and stronger until they walked right through the one from which his angel's scent emanated the strongest. The inside of the room was bare with the exception of a nest of fabric in the corner, one nearly identical to the one in his rooms.

"That does not look large enough to contain you and your brethren. That...familial nesting they spoke of prior to your departure," he commented quietly, trying to keep his voice even. His mate was in his arms. He did not need his alpha jealousy driving him away.

"We tried it. Once. My hatch-mates and I, we got a whole bunch towels and sheets and whatnot from the humans, tried to nest. I couldn't relax. I had to keep my wings wrapped in your cloak because I couldn't stand anyone else even touching a feather. It was more uncomfortable than waking up from a heat and finding myself mated to a Knight of Hell." Castiel eyes narrowed at the implication of regret and he turned his head to catch the expression on his omega's face, eyes narrowing further when he discovered only a teasing smile. "But I do feel better now. Now that you're here and now that you've...well, mounted me again. I think that might have been what was causing the problem with my health, not allowing you to mount me or reassert your mating mark on me." His mate grabbed both of his hands and started walking backwards, pulling him towards the nest. "Something I think I need to... reconsider." At his mate's tone, the alpha's brow rose and then fell as a smirk slid across his face instead.

Dean was moving slowly, carefully, keeping his eyes on his mate's as he walked. Castiel was doing his part in stripping, removing all of his coverings until his meat suit was as naked as the day it had been born. Only then did those pretty greens leave his to scan down his body, their slow path only encouraging the thickening of his erection. He may have mounted his mate a short time ago, but he was eager to do it again.

"So what you're saying is... I need to fuck the healthy back into you?" Dean's eyes went wide, breath hitching before he stumbled and almost tripped into his nest and he would have if the Knight hadn't been holding his hands so tightly.

"_Yes_," he breathed, that pretty flushing darkening his cheeks and making his grace pulse with his excitement and pleasure. "Lay down," he whispered. Castiel raised an eyebrow in intrigued surprise but did as he was bid, lowering himself slowly into the nest and leaning back, propping himself up on his elbows to watch his mate do what he really hoped he was about to do.

His angel bit his lip, his cheeks flushed as he slowly moved to stand with a leg on each side of the Knight's hips. Slowly, so slowly, he lowered himself to his knees, reaching behind himself to grasp his mate's thick cock with a firm hand. The alpha licked his lips and held his breath as Dean pressed the tip of the cock in his hand to an already-dripping hole. Bit by bit, he was engulfed in that tight, wet heat that he felt like he hadn't experienced in months. A low groan was pulled from his throat when he bottomed out and his mate was just sitting on him, hands pressed to his chest and breaths puffing from pink lips in pretty pants.

"There really is no prettier sight than you impaled on my cock," the demon murmurred. His angel's face lit up like the setting sun and his grace pulsed near-violently in a combination of embarrassment and pleasure. The tip of a tongue flicked out to wet lips and then the hands on his chest increased their pressure as his omega lifted himself up, his walls clutching at his cock like his own body was protesting the loss, and then he was dropping down again. It truly was a gorgeous sight. Castiel relaxed completely, moving his hands to his mate's stomach, supporting the bulbous girth as well as simply feeling the hardness indicative of the eggs held safely inside. He didn't bother helping his angel fuck himself on his cock, enjoying the way he was exerting himself to make his own pleasure. "That's right, angel. Take your pleasure."

"_Cas_." Dean's voice sounded absolutely wrecked and Castiel loved it. "You feel..." His omega trailed off, head falling back as he moaned and the sudden and simultaneous clenching of his passage around his cock and growing knot told him that his mate had finally found the angle that would bring him the most pleasure.

"Go on, beautiful. I feel what?" Castiel prompted, finally removing his hands from his omega's stomach and putting one on Dean's hip and the other on the bobbing cock bouncing between them and continually hitting the round stomach above, stroking it in time with the thrusts. His hand was sliding down from hip to thigh, enjoying the way it trembled beneath his grasp.

"You feel..." he groaned out, never ceasing his slow but steady fucking. "You feel so good. Like..." He trailed off again and Castiel's fingers tightened around his thigh.

"Go on, Dean."

"I feel so full. You make me so full," his beautiful angel was moaning, head still back and neck drawn long, the tip of his cock a perfect match for the colour of his parted lips. "Oh, grace, Cas, I need your knot. I need you." Dean's grace was dancing around them, uninhibited, surrounding and stroking his power just the same way his mate's passage was stroking his cock.

"You have me, angel. You'll always have me." His knot was so thick that his omega could no longer take his full length and was balanced almost unsteadily on his knees but he was close and his mate was tightening up in the way that meant he was close. He released the stiff erection in his hand, ignoring the plaintive whine it caused, and closed all ten fingers tight around slim hips. "Now, omega, come for me," he commanded, pulling hard on Dean's hips and forcing his knot past the tight ring of muscles. His mate shouted out, voice low and hoarse as he came, spurting come across Castiel's chest and clamping down tight on his knot until the Knight was coming too, fingers bruisingly tight as he filled his mate.

Dean slumped in on himself, panting and eyes dazed. Before he could fall forward onto his stomach, the alpha sat up, releasing another fresh stream of seed into his mate. His angel moaned and wrapped his arms around the Knight's neck, clutching him tightly as he shuffled backwards the short distance to prop himself up in the corner. Every few moments, his cock would pulse and his mate's passage would pulse around it in response, pulling more every last bit from it that it could. He almost couldn't wait until his omega's next heat, so he could breed him full again. They had already mated twice since his arrival, and already his mate was looking healthier, his grace glowing brighter.

"Do you really mean that, Cas?" The low voice pulled him from his thoughts with tentative fingers tracing over the scarred skin of his meat suit with featherlight brushes.

"Mean what, Dean?"

"That... that you'll always have me?"

"What reason have I given for you to doubt my words?" he asked, amused at the way his mate refused to meet his eyes. His knot deflated but his arms wrapped tight around his angel's waist to keep him from moving away.

"You've lied to me before!" Dean exclaimed, brow furrowed. Castiel furrowed his own brow in confusion before it hit him and he laughed.

"Do you mean that time I wasn't there when you woke because I was worried about your health and summoned angels that could have killed me on sight?" The omega's cheeks darkened and he still refused to meet his eyes. The Knight chuckled and unwrapped one hand only to firmly cup the other's jaw, angling his face and keeping hold until green eyes focused on him.

"Yeah," Dean admitted, tone grudging.

"Do you not think that my actions that day should speak more for my intentions than the fact that I broke a promise not worded as such in order to achieve them?" His stubborn, fiery soldier huffed and sat back, crossing his arms.

"You still broke a promise." He resisted the urge to do something as equally childish as rolling his eyes at the petulant tone. Instead, he grasped the back of his mate's neck, palm heavy right against his mating mark. It had both the desired and expected effect of his omega collapsing against him, implicit and pliant.

"Do you doubt that I will keep this one?" he murmured, right against the shell of an ear, slowly increasing the pressure of his hand. His omega was letting out quiet little whimpers against his neck, mouthing at the skin over his scent gland with blunt teeth and grinding down on the alpha cock still inside him as it began to grow erect once more.

Dean was shaking his head, but as he didn't sit up to do so, it ended up as more of a loll back and forth along his alpha's shoulder, as he groaned out, "Please don't stop. Oh grace, please don't stop, Cas. I believe you. Fucking grace, I believe you."

"Good, angel," the Knight replied, hips thrusting up into his mate's and power roiling wildly as possessive alpha instincts came to life. "Because you mine."

* * *

**That was longer than I thought it was going to be. Either way, it was tough, it was fun, and for now I'm going to mark the Series as Complete, but if the muses give me further ideas, then I'll be sure to add on. Don't forget to leave a review telling me what you thought and drop by my author tumblr (TheMadKatter13-fanfiction) to subscribe for updates and stuff.**


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